This image traces the dramatic evolution of the polar clouds of Titan, Saturn’s largest moon, throughout the seasons. At the top, polar maps from the Titan Planetary Climate Model show how cloud thickness changes around the south pole at different times of the Titanian year : the colors indicate atmospheric cloud opacity. Below, actual images taken by the Cassini mission offer a visual glimpse of these clouds as they appear from space. The clouds form very high in the atmosphere, at altitudes of over 300 km, when polar autumn begins. They then gradually descend to lower layers, changing their composition along the way, before dissipating with the return of spring. These cloud cycles likely play a key role in the transport and deposition of organic molecules on Titan’s surface, notably influencing the chemistry of its polar lakes.
Référence : de Batz de Trenquelléon, B., Rannou, P., Lebonnois, S. et al. Origin, evolution, and fate of Titan’s polar clouds. Nat Commun 17, 250 (2026).
